As an avid /fit/ poster and bodybuilder, this discussion fills me with the rage of 1000 suns. What this boils down to is obese indviduals attempting to make excuses for their weight and size. Claims that you can be obese and healthy as well as that it is impossible for some people to lose weight simply aren't true. I am all for body acceptance, if you want to eat 7000 calories of junk food a day then by all means do it. I won't make fun of you for it at all, you are free to do whatever you like. However, do not tell my generation that it is healthy to weigh 500 pounds and do not tell them that weight is only genetic and cannot be lost. This essentially promotes a lifestyle that will kill them all the while they are under the impression that it is "genetics" and they don't have to work out or make any effort to change their weight as it is "healthy".
tl;dr I am all for body acceptance but don't make excuses for your weight